Emergency firing facility for guns



July 23, 1968 HANS-DIETER HARNAU 3,393,640

EMERGENCY FIRING FACILITY FOR GUNS' Filed Aug. 30, 1966 n w M b w ,z v M W M f H 3. WW mlll wlii A T TURA/EVS States Patent O v 3,393,640 v Ely/IERGIENCYl FIRING FACILITY FOR GUNS Hans-Dieter'Harnan, Gevelsberg, Westphalia, Germany,

'assigner 'to Rheinmetall G.m.b.H., Dusseldorf, Germany, a company of Germany 'Filed Aug. 30, 1966, Ser. No. 576,014

Claims priority, application Germany, Sept. 3, 1965,

v`,.fuisTRAcTQ-oF THE DISCLOSURE An-'emergency tiring facility for guns, whereby a primer may be initiated by a I'current impulse produced in the inductioncoil` of an impulse generator through thedisplacement of its core.

' For initiating the primer with the aid of -an impulse generator it was hitherto necessary to connect theprimer in'fparallel with the induction coil of the impulse generator prior to initiation. This gives rise, however, to the drawback that,- if'the electric resistances of primers are not uniform, 'as 'is the case with many electric detonator caps,` theenergy applied to the ignition circuit will, according to the laws governing matching, 'likewise not beunifor-m. These relations are'illustratedv in' the diagram shown inv FIG." l, which shows'the energy Wz applied -to the ignition circuit and the maximal voltage Uz applied to the primer as a function of the resistance Rz of the primer. Since low-resistance'primers usually require the highest initiating energy, the-generator coil would have to be dimensioned so that the energy maximum lies in the' low-resistance region. The voltage is then correspondingly low, amounting to only a vfew volts. In the direction of the high-resistance region the energy decreasesdue tomismatch, whereas the voltage increases until almost the no-'load'level is reached.

Let a region a of the diagram beitaken in which low-. resistance, insensitive and usually voltage-independent primers are found, meaning-.that'no initiation will take place even if the applied energy is suiiicient and the voltage is quite low, e.g. l volt. If the required voltage lies above the curve for the maximal voltage Uz initiation cannot take place even if a sufliciently large energy reserve is available.

Further let a region b be taken in which highresistance, sensitive and in many cases voltage-dependent primers are found. If they require a relatively low amount of energy, they can be initiated. However, if the required amount of energy is so large that the curve for the energy Wz applied to the ignition circuit is exceeded, then they can no longer be initiated.

In summary it may therefore be said that, in the known arrangements, only such primers can be initiated with certainty which lie in a region which is both below the energy curve and above the voltage curve.

If the impulse generator is used with widely diiering primers for tiring a gun in which various types of ammunition are to be used, it may occur that, for the reasons already given, not all the primers can be initiated with one and the same impulse generator.

It is an object of this invention to provide an improved emergency firing facility for guns with which, irrespective of the electrical characteristics of the primers, always the same amount of energy with the same voltage is applied to the ignition circuit, so allowing the use of both voltage-dependent and voltage-independent detonator caps.

According to the invention this problem is solved by using for primers with widely differeing resistances an ICC impulse generator with a maximal voltage rating corresponding to the primer with the highest resistance, and by temporarily storing in a storage capacitor the electric energy generated by the displacement of the core of' the generator and applying it to the primer substantially on or shortly after the termination of current generation. As a result, it is possible to design the induction coil of the impulse generator, irrespective of the resistance of the primers, with such a high resistance that, with maximal energy, the voltage is considerably higher than in the case of known arrangements, e.g. about 100 volts. The storage capacitor is then charged with this voltage, preferably by way of a rectifier. The rectifier serves at the same time as a blocking element to prevent the capacitor from discharging back through the induction coil.

The capacitor voltage may be applied to the primer in various different ways, whereby it is only necessary to ensure that the generation of the impulse is by this time completed so that the capacitor is fully charged. This process can be controlled, for example, as a function of time. In its preferred embodiment, however, the

invention allows the primer to be connected in parallel with the capacitor by way of a switch lwhich may be actuated by the slidably supported core of the impulse generator.

This embodiment of the invention is based on the consideration that the generation of the impulse is completed by the time the core inside the impulse generator reaches a certain position. When in this position it is also certain that the capacitor will have been charged to the full voltage. It is therefore advisable to eifect the changeover when the core has reached or passed this position in which it is certain that the capacitor has been charged.

A further feature of the invention resides in that a discharging resistor is connected for reasons of safety in parallel with the capacitor so that, when the ignition circuit is open, the capacitor will be discharged again within a few seconds after the generation of an impulse.

FIG. 2 shows an embodiment for emergency tiring according to the invention in the form of a circuit diagram. An impulse generator 1 has an induction coil 2 in which the movement of a core 3 causes the generation of electric e-nergy in the for-m of an impulse through the opening of the otherwise closed magnetic circuit of the impulse generator as a result of the movement of the core. Connected in parallel with the induction coil 2 is a capacitor 4 which is charged by way of a rectifier 5 while the impulse is generated in the induction coil. Connected in parallel with the capacitor 4 is a resistor 6 which allows the capacitor to discharge if there is no primer connected to the circuit after the capacitor has been charged. The primer 7 is connected to the remainder of the circuit by way of plug contacts 9 and sockets 10. The primer 7 is replaceable, i.e. following the initiation of one primer, a new primer may be connected to the remainder of the circuit. The closure of a switch 8 for connecting the primer 7 to the circuit takes place in response to the move-ment of the core 3. When the core reaches the position c, the generation of the electric energy by the current impulse in the induction coil 2 and the charging of capacitor 4 will have been completed. The core actuates at this instant or shortly afterwards the switch 8, whereby the capacitor discharges by way of the primer 7 and initiates firing. The rectifier 5 prevents any back discharge of the capacitor through the induction coil 2.

In FIG. 3 the energy Wz and maximal volta-ge Uz' for the embodiment of the invention are shown as a function of the resistance Rz of the primer. It may be seen from this representation that the energy Wz applied to the 3 ignition circuit is, irrespective of the resistance of the primer, equal to the maximal energy Wz in the case of the embodiment represented by a curve in FIG. 1, and that the maxi-mal voltage applied to the primer is considerably higher than in the case of the embodiment shown in FIG. 1. The values of both the energy and the voltage may be chosen irrespective of the resistance of the primer by correspondingly dimensioning the induction coil of the impulse generator.

In a practical embodiment, an impulse generator 1 with a maximal voltage rating of 100 volts and an energy rating of 70 milliwatt-Seconds was used with a rectifier 5 in the form of a silicon diode type BYX l0, which has a reverse voltage of 800 lvolts, an average `forward current of 0.2 ampere, and can be loaded with an overload impulse of l5 amperes for a maximal duration of 10 milliseconds and a voltage impulse of up to 1600 volts in the reverse direction. The capacitance of the storage capacitor 4 amounted to 14 af. and a 100-kilohm resistor served as resistor 6.

With circuit elements so dimensioned, the following primers can be positively initiated:

Primer- Resistance, ohms DM 42 -.01 Hep (U.S.) 1.3-2.3 APDS (U.S.) 1.3-2.3 HEAT (U.S.) 1.1-1.7 L1A3 (Brit.) 40-100 L1A4 (Brit.) 10-160 It is seen from the foregoing examples that the embodiment is suitable for the initiation of primers with widely differing electric resistances.

What is claimed is:

1. An electrical emergency firing circuit for supplying an `electrical current impulse and adapted to be connected with an electrically initiated primer for discharging a firearm, the circuit comprising an electrical energy storing capacitor,

rectifier means for blocking fiow of electrical current in one direction therethrough,

an electrical impulse generator for generating an impulse of at least a predetermined voltage and including an induction coil connected serially through said rectifier means and in parallel `with said capacitor for conducting thereto an electrical current induced in said coil and further including magnetic structure having a displaceable elem-ent movable linearly relative to said coil for varying the linkage of said coilwith a magnetic field of said magnetic structure and thereby generating an impulse' ow of 'electrical current to charge said capacitor withelectrical energy, L separable electrical connector means `adapted to be connected with a primer, and normally open switch means actuated in response to completion of linear Imovement of said displaceable element of said generator `magnetic structure and electrically connecting said capacitor and said rseparable electrical connector means for completing an electrical circuit of said capacitor and said ,connector means and discharging electrical energy stored lbyy 4 lsaid capacitor through a primer connected to said connector means, said switch means closing upon completion of movement of said displaceable element and thereby cooperating therewith to discharge said capacitor after charging thereof to a predetermined magnitude of potential.

2. A circuit according to claim 1 and wherein said magnetic structure of said generator normally defines a closed magnetic circuit and said displaceable element opens said magnetic circuit yupon movement thereof to change the linking vof said coil by magnetic ux lines, and further comprising a charge bleeding resistor electrically connected in parallel with said capacitor for discharging the same over an extended period of time in the event discharge is not effected by said switch means.

References Cited UNITED STATES PATENTS I 2,313,101 3/1943 Stuart 310-69 2,395,600 2/ 1946 Weisglass 617-31 2,740,339 `4/1956 Carter 95-11.5 3,035,520 5/1962 Koeppen 102-70.2 3,037,148 5/1962l Gayler 310-70 X BENJAMIN BORCHELT, Primary Examiner.

T. H. WEBB, Assistant Examiner. 

